The present invention relates in general to a process for signalling cut-out protection in decentralised traffic-light installations.
The process according to the present invention relates to a signalling malfunction protection in decentralized traffic-light installations having a signalling cut-out protection and evaluation assembly in a node control unit and having a plurality of peripheral lamp switches and sensor, designated as a module and a data transceiver, which together form an LMP assembly, as well as transformers and rectifiers for associated signal generators and groups of signal generators on respective traffic-light poles, the node control unit being connected to the data transceivers of the individual LMP assemblies via a power and a data line.
Decentralised traffic-light installations have peripheral lamp switches and sensors which are accommodated decentrally from the actual node control unit for the respective groups of signal generators on the traffic-light pole. The components, required for this, consisting of a transformer and rectifiers as well as an LMP assembly for data transceivers and lamp switches with signalling cut-out protection sensors, so-called sensors, together form a PLS unit, also referred to as a PLS module. The associated signal groups are actuated from the cross connection unit via connecting lines and the PLS modules and LMP assemblies. The connection from the control unit to the individual modules can be formed by means of a specially produced cable (consisting of phase-protection, zero-protection conductors and a coaxial line) the control of the individual signal lamps and the acknowledgements occurring via the coaxial cable. A decentralised traffic-signalling installation is described, for example, in German Offenlegungsschrift 32 30 761.
The evaluation of the data, e.g. the signalling malfunction status of the signalling lamps takes place in a signalling malfunction protection microprocessor assembly, generally in the control unit. A monitoring device of this kind for traffic signalling installations with microprocessor assemblies is described in German Offenlegungsschrift 34 28 444.
In order to monitor the entire control unit and the associated signal generators, it is ensured, for example by means of system tests, that the entire installation is completely operative. In this process, for example every 300 milliseconds, a genuine malfunction can be generated at the signal generator for a short period, e.g. 2 ms, this conflict not being visible. The signalling malfunction protection microprocessor detects this and issues a corresponding signal. However, if it is not detected, the installation switches off (EP-A 1-0 251 097).
DE-PS 30 35 515 describes a circuit arrangement for operating signal generators of a traffic-light installation. In the known circuit arrangement, all the signalling lamps are supplied via a single power line, each signal generator or each signal generator group having peripheral lamp switches and sensors as well as associated data transceivers, which are connected to the control unit via a common data line.